| Summary: |
The current legislation imposes stringent limits to the emission of a great number of toxic chemical compounds, namely the volatile organic compounds (VOCs). These compounds are released during the manufacture of a wide range of consumer goods, namely by companies dealing with painting and coating, printing, dry cleaning, electronic components and agglomerates, chemical and textile industries, and they are an important source of atmospheric pollution, provoking primary and secondary harmful effects (for example, smog). In relation to Portugal, even the most optimistic projections indicate that, in 2010, the country will be far from reaching the ceiling values established by the EU directive 2001/81/CE, unless new technologies to the abatement of VOCs are introduced.
Catalytic oxidation is one the most promising technologies, being especially recommended when the concentration of VOCs is low. It presents the following advantages when compared with thermal incineration (the most widely used technique): lower energy costs (requires temperatures between 200 and 500ºC, while for thermal incineration the temperatures range from 750 to 1150 ºC) and lower investment costs of the industrial units (catalytic oxidation units may be more compact and do not need high temperature resistant construction materials).
Due to the large variety of molecules and complexity of the mixtures found, catalyst design for VOCs oxidation is not an easy task. As a result of the strict regulation for VOCs emissions, the development of catalysts capable of achieving combustion efficiencies above 95%, at temperatures as low as possible, is a major challenge. In order to ovoid the production of CO and other compounds which can be more toxic then the original effluent (such as dioxins), these catalysts must have a high selectivity to CO2.
The main objective of this project is the development of efficient and stable catalysts for the destruction of volatile organic compounds, representative of t  |
Summary
The current legislation imposes stringent limits to the emission of a great number of toxic chemical compounds, namely the volatile organic compounds (VOCs). These compounds are released during the manufacture of a wide range of consumer goods, namely by companies dealing with painting and coating, printing, dry cleaning, electronic components and agglomerates, chemical and textile industries, and they are an important source of atmospheric pollution, provoking primary and secondary harmful effects (for example, smog). In relation to Portugal, even the most optimistic projections indicate that, in 2010, the country will be far from reaching the ceiling values established by the EU directive 2001/81/CE, unless new technologies to the abatement of VOCs are introduced.
Catalytic oxidation is one the most promising technologies, being especially recommended when the concentration of VOCs is low. It presents the following advantages when compared with thermal incineration (the most widely used technique): lower energy costs (requires temperatures between 200 and 500ºC, while for thermal incineration the temperatures range from 750 to 1150 ºC) and lower investment costs of the industrial units (catalytic oxidation units may be more compact and do not need high temperature resistant construction materials).
Due to the large variety of molecules and complexity of the mixtures found, catalyst design for VOCs oxidation is not an easy task. As a result of the strict regulation for VOCs emissions, the development of catalysts capable of achieving combustion efficiencies above 95%, at temperatures as low as possible, is a major challenge. In order to ovoid the production of CO and other compounds which can be more toxic then the original effluent (such as dioxins), these catalysts must have a high selectivity to CO2.
The main objective of this project is the development of efficient and stable catalysts for the destruction of volatile organic compounds, representative of those found in industrial emissions (such as solvent emissions). The complete oxidation of different classes of VOCs will be studied using two types of catalysts: supported metals and metal oxides. In preliminary studies, Pt/TiO2 and cryptomelane type manganese oxide were identified as the most promising catalysts, the later being especially interesting from an economical point of view because no noble metal is used. In a later stage of the project, the preparation, characterization and catalytic evaluation of structured catalysts (monoliths) using the most promising active phase will be addressed, as a preliminary step for their industrial application.
Based on promising results expected from this research, consideration will be given to the extension of this project in order to optimize the catalysts and to address the setting-up of a demonstration unit, in collaboration with interested companies. |